I've noticed typology theories, such as MBTI and Socionics, are very popular in US. I'd like to ask you all a few questions. What are the consequences of it, I mean if all people would be acquainted with this theory. What would happen then? How would the world change?

Where I come from, is not even heard of it (socionics that is). Of course on a academic level, but it's not widespread across the average population. Is in US or elsewhere more present in everyday life? And also is it true they are using the tests by the employers to select their staff and it is a criterion to hire or reject job candidates?